All it takes is that pinprick of light — which measures about 1/40th candlepower — to help Burger remember images of summertime visits to his grandmother's house in Oklahoma. Just before dusk, Burger and his friends grabbed Mason jars and poked holes in the lids. Then they dashed outside to catch fireflies, also known as lightning bugs, and popped them inside the glass containers. "We would always see if we could get enough fireflies in the jar so the light would be strong enough to read by at night," Burger recalls. By morning, however, most of the bugs would be dead. Today, Burger lives in Houston and he has a different mission: He wants to help fireflies fly free and multiply. No one knows for sure — entomologists, the scientists who study bugs, haven't done any studies or surveys — but it seems the firefly population has declined over the last few years in several places where they once swarmed. The cause is equally sketchy. Marc Branham, an entomologist at the American Museum of Natural History in New York City, says it might be due to the increased use of pesticides and herbicides. It might be the encroachment of urban progress. It might be long periods of dry weather. In San Antonio and South Texas, which have been drier than normal for several years — recent downpours and floods notwithstanding — all of the bug spray and progress and droughts may have combined to put a triple whammy on lightning bugs. "We're seeing fewer fireflies in some areas recently," Branham says. "We're not sure why." Fireflies, which belong to the scientific family Lampyridae, aren't really flies at all, but beetles. Found on every continent except Antarctica, lightning bugs — the term is interchangeable with fireflies — like warm and wet conditions. Insects of summer In South Texas, the first fireflies usually appear sometime around Memorial Day. The last one flickers out about the end of July. As larvae, they feed for about a year on snails, worms and slugs. Once they emerge as winged adults, however, most lightning bugs don't eat anything at all. Instead, after lazy summer days spent poking around in grass and leaves, they take to the air after sunset. That's when they get to work. Their nighttime acrobatics and light displays — here's something kids don't know — are part of a big insect orgy. Branham, whose latest research project focuses on "firefly signal system evolution," says the pattern and duration of lightning bug flashes depend on species and gender. In general, as it is in much of the animal kingdom, it's the male that does most of the flashing, hoping to get some attention from a willing female. Courtship and love, however, have their hazards. The females of one species, for instance, can imitate the flashing signals of females from other species. In one of nature's cruel jokes — again not restricted to the world of fireflies — these females, dubbed "femme fatales," lure unsuspecting males into coming close. "Then they eat them," Branham says. In any event, it's a short-lived victory, even for those bugs that prefer to make love, not war. All adult fireflies die within a few weeks, leaving the young from their fertilized eggs to hatch and carry on the next summer. There are more than 170 firefly species in the United States and more than 1,900 around the world. In this country, lightning bugs are most common east of the Mississippi River. They are rarely found west of the Rocky Mountains, although some populations have been found in Utah. Arwin Provonsha, the curator of the Purdue University Entomological Research Collection, says fireflies hold an attraction for humans that spans generations. Even kids from today's computer generation will drop their Gameboys and Sega game controllers, at least temporarily, to run outside and catch fireflies, just like their parents and grandparents did. "It doesn't matter whether you like insects or not," Provonsha says. "Everyone has kind of a reverence for this mystical little thing that lights up in the night. It's like watching Christmas tree lights." Mankind's fascination with fireflies can extend beyond childhood. The firefly is the state insect of Pennsylvania. Researchers have uncovered the secrets of the bugs' "cold light." And at least one company still pays kids and other collectors for lightning bugs to extract compounds used to help detect cancer and other illnesses. The end of a lightning bug's tail contains several chemicals, including two called "luciferin" and "luciferase." When they combine with oxygen and adenosine triphosphate, also known as ATP, the chemical reaction produces bioluminescence, which means light by a biological process. Besides its use as a mating call, a lightning bug's light — which varies from yellow to green and even amber, according to species — also warns birds, bats and other predators that it won't make a good meal. Scientists theorize the chemicals that make the bugs' light work taste bitter to animals that would eat them. The Sigma Chemical Co. in St. Louis buys fireflies for laboratory research. A company spokesman declined to comment about the process and its impact on the firefly population. Instead, he sent a fax with information about fireflies and their scientific uses. ATP is present in all living cells, according to the information from Sigma. In medical applications, researchers can detect cancer cells, which contain low levels of ATP, by measuring their ability to produce light when combined with luciferin and luciferase. Conversely, the blood of heart attack victims contains elevated levels of ATP, which means it would produce more cold light than normal. There are other uses. "Researchers can test for very small amounts of bacteria in milk or water," the Sigma information reads. "In fact, this light producing system is so sensitive it would enable a technician to detect a single drop of contaminated water in a swimming pool." Scientists, however, have learned to create their own cold light. One of the more familiar applications: Those light sticks and glow-in-the-dark necklaces sold at rock concerts and other arena events. The devices, packed with synthesized luciferin and luciferase, activate with a snap or twist that opens an internal vial of oxygen. Tom Turpin, a professor of entomology at Purdue, says, "There's no real reason today to collect fireflies in the wild." "Years ago, there was a woman in Iowa who was known as the 'Firefly Lady' because she had collected so many over the years," Turpin recalls. "That had an impact on the firefly population, especially within the area. "Some people said, 'Why are we wiping out these insects?'" Turpin, however, is quick to add that childhood bug collections probably aren't to blame for fireflies' decline in some areas. Spreading cities Locally, experts say the increased urbanization of Bexar County and surrounding areas would have the biggest impact. Some also theorize that fire ants — a menace on the increase in South Texas — may eat firefly larvae. "Fireflies are just real sensitive to construction and climate changes, like droughts and things like that," says Nathan Riggs, an entomologist with the Texas Agricultural Extension Service in Bexar County. "If we get some good moisture and things are relatively calm in the environment, then we'll have them." That's encouraging to amateur firefly fanciers such as Burger. So far this year, Burger has had just one firefly sighting. That was a lone bug hovering near the back door of his house in the Heights, a historic neighborhood near downtown Houston. Besides lightning bugs, the 52-year-old attorney also enjoys gardening, wine, turtles and model railroading, all of which share space on his Web site at www.burger.com. The Web pages devoted to fireflies range from scholarly papers on Lampyridae to an account of a firefly-repopulation project in Japan. Burger says he hopes his site snares some special attention. "I set that site up in the hopes that somebody somewhere in the U.S. will tell me, 'Sure you can buy firefly eggs. You just go over here and they're selling them,'" Burger says. "And then I could reintroduce them to the Heights. But so far, I haven't found a commercial firefly source." One of the features on Burger's Web site is a section filled with e-mail posts on firefly sightings. Burger gets them from people all over the world. He highlights the names of the correspondents' hometowns in boldface. "You can get an idea at a glance how widespread fireflies still are," Burger says wistfully. "Like in the old days, when you could just walk out in your back yard and there would be a back yard full of them." duhler@express-news.net
07/23/2002